4,4 - bis(trifluoromethyl) - 2,2,2 - triphenyl-3-triphenylphosphoranylidene)-1,2-oxaphosphetane



United States Patent O 3,488,408 4,4 BIS(TRIFLUOROMETHYL) 2,2,2TRIPI-IEN- YL-3-TRIPHENYLPHOSPHORANYLIDENE)-1,2- OXAPHOSPHETAN E Gail H.Birum, Kirkwood, and Clifford N. Matthews, St. Louis, Mo., assignors toMonsanto Company, St. Louis, Mo., a corporation of Delaware No Drawing.Filed Dec. 29, 1966, Ser. No. 605,592 Int. Cl. C07d 105/02; C07f 9/54;A01n 9/36 US. Cl. 260-927 7 Claims ABSTRACT OF THE DISCLOSURE4,4-bis(trifiuoromethyl)-2,2,2-triphenyl 3(triphenylphosphoranylidene)-l,2-oxaphosphetane, its thermal cleavageproduct and the acid adducts of both. The compounds are usefulintermediates for other chemical compositions and they can also be usedas pest controlling agents, textile auxiliaries, additives for petroleumproducts, means for flame proofing polymers, ion exchangers and thelike. The parent compound is the reaction product ofhexaphenylcarbodiphosphorane and hexafiuoroacetone.

BACKGROUND OF THE INVENTION In the formation of phosphine oxide andolefinic prod ucts from phosphorane and carbonyl reactants, it isusually assumed that reaction proceeds by way of a betaine which cleavesvia an unstable cyclic transition state (G. Wittig and G. Geisler, Ann.,1953, 580, 44; S. Trippett, Quart. Rev., 1963, 17, 406; and A. W.Johnson, Ylid Chemistry, Academic Press, New York, 1966). In cases wherestable intermediates have been isolated, it is generally believed thatthese intermediates have an ionic, betaine type strucure. Therefore,when hexafiuoroacetone and hexaphenylcarbodiphosphorane react, it wouldbe expected that the resulting adduct, if stable, would have thefollowing betaine structure in which both of the phosphorus-containinggroups are ionic and identical.

wherein represents phenyl (C H However, the adduct obtained has insteadone. of the phosphorus atoms in a non-ionic, pentacovalent form as partof an unusual cyclic structure and the other as part of a phosphorusylid substituent of the ring. The unexpected stability of this novelstructure is believed due to the trifluoromethyl and phosphorus ylidsubstituents.

SUMMARY OF THE INVENTION In accordance with this invention there isprovided 4,4- bis(trifluoromethy1)-2,2,2 triphenyl 3(triphenylphosphoranylidene)-l,2-oxaphosphetane, its thermal cleavageproduct and acid adducts of both.

The new oxaphosphetane (II) is a non-ionic four-membered ring compoundcontaining pentacovalent phosphorus in the ring and a phosphorus ylidsubstituent on the ring.

. The relationship of the various new compounds of this invention andthe process for producing them is best illustrated by the series ofequations below.

tax

X is an acid anion.

The starting material, hexaphenylcarbodiphosphorane (III), is more fullydescribed in United States Patent 3,262,971, issued July 26, 1966.

The new phosphorus compounds of this invention can be used as pestcontrolling agents, textile auxiliaries, means for soil amelioration,disinfectants (bactericides and fungicides), detergents, additives forpetroleum products, means for flamerproofing polymers, ion exchangersand the like.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The oxaphosphetane (H) of thisinvention is readily prepared by allowing hexaphenylcarbodiphosphoraneand hexafiuoroacetone to react at a temperature from about 20 to aboutdegrees centigrade and preferably from about 20 to about 75 degreescentigrade for such a length of time as is needed to consume all of thehexaphenylcarbodiphosphorane. The completion of the reaction is readilynoted by the disappearance of the yellow color of thehexaphenylcarbodiphosphorane; the desired product (II) is white. Thethermal cleavage product, l,l-bis(trifluoromethyl) 2(triphenylphosphoranylidene)ethylene (V), is readily obtained by heatingthe oxaphosphetane (II) to a temperature of at least '90 degreescentigrade and preferably from about 1 10 to degrees centigrade. Thethermal cleavage is advantageously facilitated by carrying out thecleavage reaction in the presence of an inert diluent such aschlorobenzene, xylene, diglyme and other liquids which have boilingpoints above the temperature of the reaction.

The acid adducts of II and V are prepared by reacting an acid with II orV or by reaction with acid followed by metathesis. HX in the previouslydiscussed equations represent salt forming acids whether they bemonoacidic or polyacidic. Thus HX exemplifies hydrochloric acid,hydrobromic acid, hydroiodic acid, trifluoroacetic acid, sulfuric acid,fluoroboric acid, phosphoric acid and the like. Exchange of anions bymetathesis is also possible. For example, replacement of bromide byreaction of IV or VII (X=Br) with sodium tetraphenylboron yields IV orVII (X=B Generally it is preferred that the reactants be present instoichiometric quantities or with a slight excess of the most easilyremoved reactant. For example, when reactinghexaphenylcarbodiphosphorane and hexafiuoroacetone, an excess ofhexafiuoroacetone would be preferred. In the same way in preparing thesalts a slight excess of the acid is to be preferred.

The following examples are illustrative of the invention and unlessotherwise specified all parts are by weight and all temperatures areexpressed as degrees eentigrade.

EXAMPLE 1 Gaseous hexafluoroacetone was dispersed in a stirred mixtureof hexaphenylcarbodiphosphorane (III) (21.4 grams, 0.04 mole) and drydiglyme (65 grams) under nitrogen at 4050 C. The flow ofhexafluoroacetone was continued for /2 hour after the yellow color ofthe hexaphenylcarbodiphosphorane disappeared. The reaction mixture wasthen cooled at for three hours and filtered under nitrogen. Theresulting product was washed with diglyme and diethyl ether to obtain21.5 grams (76 percent yield) of 4,4-bis(trifluoromethyl)-2,2,2triphenyl- 3 (triphenylphosphoranylidene) 1,2 oxaphosphetane (II), awhite solid, melting point 155-157 (decomposition: 157-158 fromdiglyme-diethyl ether). Molecular weight by vapor pressure osmometry inbenzene: 706 and 700 (theoretical for a 1:1 adduct, 702.6). The P NMRspectrum exhibited doublets of equal area at --7.3 10.2 p.p.m. and at-+54.0- -1.0 p.p.m., 1 4717 c.p.s. (relative to H PO and measured in asaturated methylene chloride solution at both 24.3 and 40.5 mc.). The FNMR spectrum had a doublet at +7 1.2i0.2 p.p.m. (relative to CCl F), J0.8 c.p.s. The H NMR spectrum had a multi-peak aryl hydrogen region at6.5 to +8.0 p.p.m. (relative to tetramethylsilane).

Analysis.Calculated for C H F OP C, 68.37; H, 4.30; F, 16.22; P, 8.82.Found: C, 68.17; H, 4.25; F, 16.27; P, 8.91.

EXAMPLE 2 A 1.0 gram portion of the adduct ofhexaphenylcarbodiphosphorane and hexafluoroacetone (Example 1) wasstirred in 5 grams of diglyme as 1.5 grams of 65 percenthexafluorophosphoric acid was added dropwise. Heat of reaction raisedthe temperature to 45. The reaction mixture was stirred for two hoursand then diluted with ether to precipitate 1.1 grams of white powder(IV) (X=PF Recrystallization from diglyme by precipitation with ether,and drying at 50/ 0.1 mm. gave 1.0 gram (83 percent yield), M.P.213-2135 (dec.). The P NMR spectrum in acetonitrile contained amoderately broad peak at 21.6 p.p.m. and a heptet at +1448 p.p.m. (J 706c.p.s.); the P NMR spectrum contained a singlet at +71.6 p.p.m. and adoublet at +725 p.p.m. (J 709 c.p.s.), the area ratio of singlet todoublet being 1:1; the H NMR spectrum contained an aryl proton region at-7.1 to 8.0 p.p.m. and a broad hydroxylic proton peak at --6.3 p.p.m.,the areas approximating the theoretical :1 ratio.

Analysis.Calculated for C H F OP C, 56.65; H, 3.68; F, 26.88; P, 10.96.Found: C, 56.62; H, 3.79; F, 27.12; P, 11.17.

EXAMPLE 3 A mixture of 1.0 gram of II, prepared in Example 1, in 6 gramsof diglyme was stirred as 0.5 gram of 48 percent fluoroboric acid wasadded dropwise. After 1.5 hours, 1.1 grams of white solid wasprecipitated by addition of ether. Recrystallization by addition ofether to a solution in diglyme-acetonitrile, and drying at 60/0.l mm.,gave 0.9 gram (80 percent yield) of white solid, M.P. 215- 215.5 (dec.).The F NMR spectrum measured in CH CN contained peaks at +70.3 p.p.m. andat +150.3 p.p.m. in a 3:2 area ratio; the P NMR spectrum contained amoderately broad peak at 22.0:1.1 p.p.m.; the H NMR spectrum containedan aryl proton region at 7.1 to 8.0 p.p.m. and a broad hydroxylic peakat +6.25 p.p.m., approximating a 30:1 ratio.

Analysis-Calculated for C H BF OP C, 60.75; H, 3.96; B, 1.37; F, 24.05;P, 7.84. Found: C, 6067; H, 4.20; B, 1.20; F, 23.81; P, 7.74.

4 EXAMPLE 4 A mixture of 1.0 gram of II, prepared in Example 1, and 5grams of diglyme was stirred as 0.5 gram of 48 percent hydrobromic acidwas added dropwise. After 0.25 hour ether was added to precipitate asolid product which was recrystallized from diglyme-acetonitrile to give0.5 gram of light tan solid, M.P. 213213.5 (dec.). The P NMR spectrummeasured in CH CN contained a broad peak at 22.0 p.p.m.; and the F NMRspectrum contained a singlet at +71 p.p.m.

Analysis.Calculated for C H BrF OP C, 61.30; H, 3.99; Br, 10.20; F,14.56; P, 7.92. Found: C, 60.65; H, 4.02; Br, 10.76; F, 15.08; P, 7.75.

Chloride and iodide salts were similarly prepared by addition ofhydrochloric and hydriodic acids to II.

EXAMPLE 5 A solution of 0.5 gram of sodium tetraphenylboron [NaB(C H inmethanol was added dropwise to a stirred solution of 0.7 gram of thebromide salt (Example 4) in methanol. The reaction mixture was stirredfor 0.5 hour at room temperature and then filtered. The product waswashed with methanol and with distilled water and dried at 60/0.1 mm. togive 0.8 gram of white powder, M.P. 130-137 (dec.)

Analysis.-Calculated for C H BF OP F, 11.13; P, 6.06. Found: F, 11.15;P,5.89.

EXAMPLE 6 A mixture of 38.0 grams of the adduct ofhexaphenylcarbodiphosphorane and hexafluoroacetone, prepared accordingto Example 1, and 35 grams of chlorobenzene was stirred and warmed at-126" C. for 5 minutes under nitrogen. The resulting dark red solutionwas cooled at 5 C. for 20 hours and then filtered under nitrogen. Theproduct was washed with ether to give 18.7 grams of an orange solidmixture. The P NMR spectrum of a benzene solution of this orange solidconsisted of a singlet at 24.5 p.p.m. for triphenylphosphine oxide and asinglet at 4.1 p.p.m., the latter singlet and an F doublet at +61.4p.p.m. (J 3.5 c.p.s.) being at tributed to1,1-bis(trifluoromethyl-Z-(triphenylphosphoranylidene) ethylene (V). Thearea ratio of the P singlet at 24.5 p.p.m. to that at 4.1 p.p.m. was4:3.

EXAMPLE 7 A 5.0 grams portion of the mixture of1,1-bis(trifiuoromethyl)2-(triphenylphosphoranylidene)ethylene (V) andtriphenylphosphine oxide from Example 6 was dissolved in 20 ml. of drybenzene, and the resulting orange solution was stirred under nitrogen atambient temperature as anhydrous hydrogen chloride was dispersed belowthe surface. The hydrogen chloride treatment was discontinued when thelast trace of orange color disappeared, and the reaction mixture wasfiltered under nitrogen. The product was washed with benzene and etherand then recrystallized from diglyme-acetonitrile to give 1.6 grams of2,2-bis(trifluoromethyl)vinyltriphenylphosphonium chlo ride (VII), awhite solid, M.P. 153-154 (decomposition). The P NMR spectrum of asolution in CdCl had a single peak at 17.3 p.p.m.; the H spectrum had adoublet at 9.1 p.p.m. (J 8.5 c.p.s.) and aryl hydrogen multiplets at 7.5to -8.3 p.p.m., the areas approximating a 1:15 ratio; and the F spectrumhad quartets of equal area at +58.1 and +632 p.p.m. (I 7.5 c.p.s.).

Analysis.Calculated for C H CIF P C, 57.34; H, 3.50; Cl, 7.69; F, 24.74;P, 6.72. Found: C, 57.24; H, 3.69; Cl, 7.93; F, 24.68; P, 6.73.

Triphenylphosphine oxide (2.2 grams), having infrared and NMR spectraessentially identical to those of an authentic sample was isolated fromthe filtrate obtained after the hydrogen chloride treatment.

The foregoing examples have been described in the above specificationfor the purpose of illustration and not limitation. Many othermodifications and ramifications 5 based on this disclosure willnaturally suggest themselves to one skilled in the art. These areintended to be comprehended as within the scope of this invention.

Having thus described our invention, what we desire to claim and secureby Letters Patent is:

1.4,4-bis(trifluoromethyl)-2,2,2-triphenyl-3-(triphenylphosphoranylidene)-1,2-oxaphosphetaneand the acid adducts thereof with an acid selected from the classconsisting of hydrochloric, hydrobromic, hydroiodic, trifiuoroacetic,phosphoric, sulfuric, fluoroboric and hexafluorophosphoric acids andhydrogen tetraphenylboron.

2.4,4-bis(trifluoromethyl)-2,2,2-triphenyl-3-(triphenylphosphoranylidene)-1,2-0xaphosphetane.

3. The acid adducts of 4,4-bis(trifluoromethyl)-2,2,2- triphenyl 3(triphenylphosphoranylidene)-1,2-oxaphosphetane having the formula(CaHQaP X- P (051193 where X is an anion selected from the classconsisting of -Cl, -Br, -I, O(O)C.CF -PO -SO -BF PF and -B (phenyl) 4.The adduct according to claim 3 wherein X is PF 5. The adduct accordingto claim 3 wherein X is BF 6. The adduct according to claim 3 wherein Xis bromine.

7. The adduct according to claim 3 wherein X is B(C6H5)4' No referencescited.

CHARLES B. PARKER, Primary Examiner A. H. SUTTO, Assistant Examiner US.Cl. X.R.

